The invention relates to xerographic process control, and more particularly, to a system for defining photoreceptor behavior during photoreceptor aging and for periodically adjusting xerographic parameters in response to the defined behavior.
Xerographic control is well known in the prior art. The art is replete with various sensors and systems for charging control, for exposure and illumination control, for developer control, and for measuring toner concentration and adjusting toner dispensers. For example, U.S. Pat. No. 4,348,099 discloses the uses of test patches, an infrared densitometer, and an electrometer for charge, illumination, toner dispenser, and developer bias control.
One difficulty with prior art systems has often been the need for costly sensors such as infrared densitometers and electrometers. Another difficulty has been the inability to account for significant electrostatic distinctions between photoreceptor surfaces on different machines or to account for significant electrostatic distinctions between different segments of the same photoreceptor surface on a given machine. It would be desirable, therefore, to provide more reliable photoreceptor voltage control to produce higher quality copies over the life of the photoreceptor, in particular, to account for variable photoreceptor characteristics to maintain more reliable photoreceptor voltage.
It is an object, therefore, of the present invention to provide new and improved photoreceptor voltage control by periodically initiating a photoreceptor characteristic analysis and automatically adjusting photoreceptor charging levels in response to the analysis to maintain more reliable and predictable photoreceptor voltage levels. Other objects and advantages of the present invention will become apparent as the following description proceeds, and the features characterizing the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.